May 2010 Archives

A good article that starts a comparison that is long over due. Not enough is being said today about comparing the various "green" alternatives. Today, most press goes to solar panels and PV. Solar connectors, even though a better investment, gets short mention. And of course, rainwater hardly gets no mention as a possible good investment. Hopefully this will be the first of many, many articles comparing the alternatives.

The Advantages of Rainwater Harvesting Over Other Sustainable Options

Sustainable options, green options and renewables - the pressure is on
us to do each one of these, and we know we should. However, it all
seems so difficult and it is expensive and the return on the investment
could be so long. We might not even be alive to see the benefit.

Rainwater harvesting is one of these options and is something we can all
understand quite easily. After all, our ancestors were doing it for
centuries until mains water arrived, and it is not rocket science.
Generally people with gardens have one or two water butts. Rainwater
harvesting is just using water butts on a much larger scale and using
rainwater for far more than just watering the garden. Fifty percent of
the 150 litres of water we use daily does not have to be mains water,
that is to say, drinking quality. 30% literally goes down the toilet.

Every rainwater harvesting system should incorporate both both passive and active. Most active
systems do due to overflow design requirements. However, system design should
start with passive and not just end with it.

Will's rainwater
catchment system is a great example of this. His completed system comprises both
an active and several passive rainwater catchment systems. Uniquely to this design is that the active system can also be used
passively.

The house is
approximately 1,610 square feet and could possibly capture about 12,000 gallons a
year in total (i.e. .623 x 1,610 x 12 inches. Canales typically capture about 75% off a flat roof of
the total runoff, or approximately 9,000 gallons a year. In this case, the canales are
located on different sides of his existing houses with muture landscaping and
small city lot.

Consequently,
trenching around the house to install 1 or 2 below ground active rainwater catchment tanks would have been
cost prohibitive. A far better design was to use the water in the existing beds
near the existing canales. Passive drainage pipes with attractive rain chains
and clay pots were used on the most visable sides of his house (i.e. the roof
and the rear patio), while on the very back side of the house downspouts feed
directly into a passive irrigation system.

Every system and every site is different; however, passive should always be included in every design if at all possible. To see more details of this site or visit other HarvestH2o projects, visit Will's house.

The rate of uptake of rainwater harvesting (RWH) in the UK has been slow
to date, but is expected to gain momentum in the near future. A number
of factors have so far contributed to the lack of progress: ambiguity in
the financial viability, lack of experience and the absence of well-run
demonstration sites. Although some technical guidance is available, the
costing information provided is sketchy and there is limited advice on
the appropriate system sizing methods to use. However, RWH is now
explicitly mentioned in key government documents such as the Building
Research Establishment's Environmental Assessment Method and the Code
for Sustainable Homes.

In an article in Water Science and Technology the authors
recommend that continuous simulation methods should be adopted, since
the simple tools currently used lead to the oversizing of tanks and
excessive capital costs.

The authors evaluate the designs of two different new-build RWH
systems using three different methods within a modelling tool: (1) a
continuous simulation which can utilize daily rainfall and demand time
series based on the yield-after-spill approach; (2) a simplified version
of the AR/D (catchment area times average rainfall divided by average
demand) approach; and (3) a simple rule-of-thumb method recommended by
the Environment
Agency (EA) which sizes the tank based on a user-defined percentage of
average annual rainfall or demand (whichever is the lower).

The two case studies were a university building and a housing
development; the RWH systems were shown to meet 46% and 36% of WC
demand, respectively. It was found that design methods (2) and (3)
overestimated tank sizes. Despite this, it was found that average annual
financial savings for method (2) was equivalent to that of method (1).
However, payback periods would be significantly longer for method (2)
due to the higher capital costs of larger tanks. Continuous simulation
(method (1)) therefore provides a better assessment of tank size in
terms of cost-benefit analysis
for a particular demand. In addition, the authors found that levels of
demand met were limited by the catchment area size, which also had
implications for financial savings. This indicates not enough
consideration is given to the catchment size when designing a RWH
system.

Water rates continue to rise. Lake Tahoe and Clovis, New Mexico lead the current list of large increases at 70% and 65% respectively.

Water has been way too inexpensive for way too long. But the days of cheap water are ending due to multiple pressures: population growth in areas of little rain or natural water sources (i.e. Phoenix, Las Vegas, Albuquerque); natural drought cycles (i.e. Atlanta, California); and our aging and decaying water infrastructure, The bad thing is that rates will continue to increase whether we conserve or not. If we don't conserve rates will just escalate faster as cities and towns try to solve the ever increasing demand for water by either drilling deeper and deeper more costly wells or by building piping systems to haul water from far away places (e.g. Las Vegas, NV). These both will ensure water price increases for the foreseeable future not just due to the costs of the projects, but also due to the rising rate of electricity which they require.

Even in these harsh economic times, local companies and politicians are approving double digit water rate increases. That they are willing to do this during these times, shows the real extent of the problem.

The good thing about these increases is that they will drive more and more installations of rainwater catchment. Money talks and the pain of paying high monthly water bills will drive individuals to consider other alternatives. It did for me. I installed my first system due to rising rates over a decade ago when my water bill started hitting $100 a month. The payback was long then, but has declined substantially since then due to rising water rates.

Today, installing some type of rainwater catchment system, either passive or active, is starting to just make good economic sense!

The most surprising tourist attraction in Portland, Ore., is its storm sewer system. Eco-friendly tourists flock to the city to understand how Portland's innovative system of curbs, gutters, roofs and rain gardens sharply cuts water pollution. When we started this 10 or 12 years ago, there was a lot of skepticism," says Dean Marriott, director of Portland's Bureau of Environmental Services. "Today, many cities are moving in this direction. People want to see how it's done.

About 50,000 homeowners have disconnected their gutter downspouts from
the storm-water system -- the cheapest way to improve storm-water
quality. The water flows from rooftops into gardens and rain barrels.
The city rewards homeowners with signs that say, "I disconnected my
downspout for clear rivers." Read Full Article >>

How many gallons of water does it take to produce $1 worth of sugar, dog and cat food, or milk? The answers appear in the first comprehensive study in 30 years documenting American industry's thirst for this precious resource. They estimated water use among more than 400 industry sectors -- from finished products to services -- using a special computer model. The new data shows that most water use by industry occurs indirectly as a result of processing, such as packaging and shipping food crops to the supermarket, rather than direct use, such as watering crops. Among the findings for consumer products: It takes almost 270 gallons of water to produce $1 worth of sugar; 200 gallons of water to make $1 worth of dog and cat food; and 140 gallons of water to make $1 worth of milk. Read the Full Story >>

Pumping more water or increasing water transfer from other
areas is not going to solve this problem. Increased pumping and
transferring water from further locations increases the need for more
power generation and this directly translates into more power plants.
For those of us who love our amazing vistas and crystal clear blue
skies, the solution to our water needs can't involve polluting our
skies. Clearly, we must look to other solutions to solve our water
needs. Full Article on HarvestH2o >>